River Flood Warning 129, NWS Seattle, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
910 AM PST WED DEC 9 2015

.SYNOPSIS...FLOOD WARNINGS CONTINUE ON A NUMBER OF RIVERS IN WESTERN
WASHINGTON. ANOTHER VIGOROUS FRONT WILL MOVE THROUGH THE AREA LATE
TONIGHT AND THURSDAY MORNING. COASTAL FLOODING IS POSSIBLE ON THE
COAST AROUND HIGH TIDE THURSDAY AND FRIDAY. ANOTHER STRONG FRONT
WILL MOVE THROUGH THE AREA ON SATURDAY.

&&

.SHORT TERM...WESTERN WA IS IN THE COOL SHOWERY AIR BETWEEN WEATHER
SYSTEMS TODAY. THE FLURRY OF THUNDERSTORMS AROUND DAYBREAK HAS
DIMINISHED BUT IT WILL BE AWHILE BEFORE THE BLUSTERY WINDS SUBSIDE
AS THE LOW PRESSURE TROUGH FILLS AND MOVES INLAND OVER BRITISH
COLUMBIA. THE FRONT AND LOW PRESSURE SYSTEM IS ALREADY WELL DEVELOPED
OFFSHORE. RAIN WITH THIS NEXT SYSTEM SPREADS TO NORTHERN CALIF AND
OREGON LATE THIS EVENING AND INTO WRN WA AFTER MIDNIGHT AND THE
BLUSTERY FRONTAL PASSAGE WILL OCCUR BY DAYBREAK THURSDAY OVER
SOUTHWEST WA AND THE COAST. THERE IS A HIGH WIND WATCH UP FOR THE
COAST FOR THIS FRONT AND THE WINDS ASSOCIATED WITH THE DEEP LOW.
THE LOW PRESSURE AREA WILL BE FAIRLY STATIONARY THURSDAY AFTERNOON
AND NIGHT...SOUTHWEST OF VANCOUVER ISLAND...AND IT WILL WEAKEN
THURSDAY NIGHT AND FRIDAY AND THEN COME ASHORE AS A TROUGH ROTATES
ABOUT THE LOW AND ARRIVES ON THE WA AND ORE COAST MIDDAY FRI. SHOWERS
SHOULD TAPER OFF FRIDAY NIGHT AND THEN THE NEXT VIGOROUS FRONTAL
SYSTEM ARRIVES DURING THE DAY SATURDAY.

.LONG TERM...THE EXTENDED FORECAST FOR SUNDAY ONWARD WILL BE A
LITTLE QUIETER AS A TROUGH DEVELOPS OVER THE INTERMOUNTAIN WEST.
SYSTEMS DRIVING SOUTHEAST ALONG THE COAST WILL GIVE SHOWERS AT
TIMES...AND SNOW LEVELS WILL FALL TO 1500 TO 2000 FEET AS WE GET TO
THE MIDDLE OF NEXT WEEK. THE GFS AND ECMWF BOTH BRING SOME CHANCE
FOR SPOTTY LOWLAND SNOW SHOWERS AT TIMES BY MIDWEEK...BUT CONFIDENCE
IN THE MODELS IS NOT HIGH ENOUGH TO MOVE THE FORECAST IN THAT
DIRECTION YET. ALBRECHT

&&

.AVIATION...STRONG MOIST WESTERLY FLOW ALOFT WILL CONTINUE TODAY
THEN TURN SOUTHERLY TONIGHT AS A STRONG FRONT APPROACHES. AT THE
SURFACE STRONG ONSHORE FLOW WILL EASE TODAY. SKIES WILL BE CLOUDY
TODAY WITH SUN BREAKS. THE AIR MASS IS SLIGHTLY UNSTABLE WITH
SCATTERED SHOWERS. CONDITIONS WILL BE MOSTLY LOW END VFR OR MVFR.

KSEA...DISCUSSION ABOVE APPLIES. MVFR CEILINGS WITH OCCASIONAL VFR.
WIND SW 20G30KT EASING TO 10G15KT IN THE AFTERNOON. CHB

&&

.MARINE...STRONG ONSHORE FLOW WILL EASE THIS AFTERNOON. HAD TO ISSUE
A GALE WARNING FOR THE NORTH INTERIOR WATERS THIS MORNING. OVER
INLAND WATERS WINDS SHOULD EASE BELOW GALE THIS AFTERNOON. ANOTHER
STRONG SYSTEM WILL APPROACH THE COAST TONIGHT AND WILL PROBABLY
ISSUE GALE WARNINGS FOR THAT IN THE AFTERNOON FORECAST.

BIG WAVES ARE FORECAST TO BEGIN REACHING THE COAST THURSDAY. TIDAL
ANOMALIES CONTINUE TO RUN ABOUT PLUS 1.5 FEET. EXPECT THE TIDES
TO CONTINUE RUNNING HIGHER THAN THE PREDICTION THE NEXT SEVERAL DAYS
DUE TO THE EFFECTS OF PERSISTENT LOW PRESSURE. A COASTAL FLOOD WATCH
IS IN EFFECT THIS MORNING THROUGH THURSDAY AFTERNOON BUT PROBLEMS
ARE MOST LIKELY AROUND HIGH TIDE THURSDAY...THE FEW HOURS AROUND
NOON. THE WATCH MAY BE EXTENDED INTO FRIDAY AS WELL. CHB

&&

.HYDROLOGY...THE RAIN HAS TURNED TO SHOWERS AND THE SNOW LEVEL IS
FALLING BACK DOWN TO PASS LEVEL. IN GENERAL RIVERS FLOWING OUT OF THE
CASCADES WILL CREST LATER TODAY AND TONIGHT. MAJOR FLOODING IS
OCCURRING ON PARTS OF THE NISQUALLY...COWLITZ...PUYALLUP AND SNOQUALMIE.
THE SKYKOMISH AT GOLDBAR CRESTED EARLIER ABOVE MAJOR FLOOD STAGE AND
THE SNOHOMISH WILL RISE ABOVE MAJOR FLOOD STAGE LATER TODAY. MOST
OTHER RIVERS HAVE OR WILL EXPERIENCE MINOR TO MODERATE FLOODING TODAY.
RIVERS WILL BE CRESTING LATER TODAY AND TONIGHT. THE EXCEPTION TO THIS
IS THE SLOW MOVING CHEHALIS WHICH WILL CREST LATER TONIGHT AT CENTRALIA
AND THURSDAY INTO FRIDAY FOR THE LOWER REACHES.

MAJOR FLOODING HAS BEEN OCCURRING ON THE SKOKOMISH RIVER FOR THE
LAST FEW DAYS AND WILL CONTINUE TODAY. THE RIVER IS EXPECTED TO FALL
BELOW MAJOR FLOOD STAGE ON THURSDAY.

IN ADDITION TO THE FLOODING THE INCREASED THREAT OF LANDSLIDES DUE
TO THE HEAVY RAIN WILL CONTINUE TODAY.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...

WA...FLOOD WATCHES AND NUMEROUS FLOOD WARNINGS ARE IN EFFECT.
     WINTER WEATHER ADVISORY IN EFFECT FOR THE CASCADES.
     COASTAL FLOOD WATCH AND HIGH WIND WATCH NORTH AND CENTRAL COAST.

PZ...GALE WARNING COAST...STRAIT...INLAND WATERS.
	 SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

WWW.WEATHER.GOV/SEATTLE

AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION CAN BE SEEN
ATWWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SEATTLE WA
912 AM PST WED DEC 09 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0800 AM     HEAVY RAIN       2 N POTLATCH            47.40N 123.14W
12/09/2015  M3.10 INCH       MASON              WA   TRAINED SPOTTER

            24 HOUR TOTAL.

&&

JSMITH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SEATTLE WA
951 AM PST WED DEC 09 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0530 AM     HEAVY RAIN       2 NNE PUYALLUP          47.21N 122.26W
12/09/2015  M2.53 INCH       PIERCE             WA   TRAINED SPOTTER

            24 HOUR TOTAL

&&

JSMITH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SEATTLE WA
1104 AM PST WED DEC 09 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1000 AM     HEAVY RAIN       1 E MARBLEMOUNT         48.53N 121.43W
12/09/2015  M2.40 INCH       SKAGIT             WA   TRAINED SPOTTER

            24 HOUR TOTAL

&&

JSMITH